What is the Fate of Undisplaced Femoral Neck Fractures Treated With Cannulated Screws?

BACKGROUND

We aimed to report implant survival in Garden type I and II femoral neck fractures treated with cannulated screws in elderly patients.

METHODS

We retrospectively studied 232 consecutive unilateral Garden I and II patients (232 fractures) treated with cannulated screws. Mean age was 81 years (range, 65 to 100), and a body mass index of 25 (range, 15.8 to 38.3). No between-group differences were found in demographic variables and/or baseline measurements (P > .05). Mean follow-up was 36 months (range, 1 to 171). Two observers measured baseline radiographic variables with good-to-excellent interobserver reliability. The posterior tilt angle, measured on a cross-table lateral x-ray, was used to classify the cohort into <20° (n = 183) and ≥20° (n = 49). The cumulative incidence with competing risk analysis was used to predict association between posterior tilt and subsequent conversion to arthroplasty. Patient survival was calculated with the Kaplan-Meier estimate.

RESULTS

Implant survival was 86.3% (95% confidence interval (CI) 80 to 90) at 12 months and 77.3% (95% CI 64 to 86) at 70 months. The 12-month cumulative incidence failure was 12.6% (95% CI 8 to 17). After controlling for confounders, posterior tilt ≥20° had higher risk of subsequent arthroplasty when compared to posterior tilt <20° (38.8 [95% CI 25 to 52] versus 5% [95% CI 2.8 to 9], subhazard ratio 8.3, 95% CI 3.8 to 18), without any other radiologic or demographic factor being associated with failure. Patient survival was 88.2% (95% CI 83 to 91.7) at 12 months, 79.5% (95% CI 73 to 84) at 24 months, and 57% (95% CI 48 to 65) at 70 months.

CONCLUSION

Cannulated screws were a reliable treatment for Garden I and II fractures, except when there was posterior tilt ≥20°, where arthroplasty should be considered.

Successful hip revision surgery following refracture of a modern femoral stem using a cortical window osteotomy technique: A case report and review of literature

BACKGROUND

The ExeterTM Universal cemented femoral component is widely used for total hip replacement surgery. Although there have been few reports of femoral component fracture, removal of a broken femoral stem can be a challenging procedure.

CASE SUMMARY

A 54-year-old man with a Dorr A femur sustained a refracture of a primary ExeterTM stem, two years after receiving a revision using a cement-within-cement technique (CWC) through an extended trochanteric osteotomy (ETO). The technical problems related to the CWC technique and the ETO played a major role in the stem fatigue refracture. We performed revision surgery and removed the distal cement using a cortical femoral window technique, followed by re-implantation with an uncemented, modular, distally-fixed uncemented stem. The patient experienced an uneventful postoperative recovery.

CONCLUSION

Re-fracture of a modern femoral ExeterTM stem is a rare event, but technical complications related to revision surgery can lead to this outcome. The cortical window osteotomy technique can facilitate the removal of a broken stem and cement, allowing for prosthetic re-implantation under direct vision and avoiding ETO-related complications.

Do nonagenarians have more complications and unplanned readmissions than octogenarians following primary THA? A retrospective cohort study

INTRODUCTION

The performance of total hip arthroplasty in elderly patients, especially nonagenarians, is challenging due to higher patient frailty and medical comorbidities. We compared 90-day postoperative complications and unplanned readmissions between nonagenarians and octogenarians undergoing elective THA.

METHODS

One hundred and eleven patients undergoing elective, unilateral THA were retrospectively analyzed. Forty-four patients were nonagenarians (Group A), and 67 patients were octogenarians (Group B). Demographic data included age, gender, body mass index (BMI), ASA score and Charlson Comorbidity Index (CCI). Frailty was defined according to the Rockwood Frailty Index. All patients underwent a thorough preoperative assessment through a specific institutional clinical pathway created for this matter. Postoperative adverse events were grouped into major or minor. A regression model was used to evaluate independent risk factors for the development of complications.

RESULTS

There were no differences in the ASA score (65.9% vs. 53.7% ASA III-IV), prevalence of frailty (1% vs. 9%) and comorbidities between both groups (p > .05). The CCI was higher in nonagenarians (p = 0.007). Nonagenarians had more in-hospital complications, although most were minor (p = 0.002), none of which resulted in mortality. Ninety-day unplanned readmissions were similar between groups, with 4 (9.1%) and 6 (9%) in groups A and B, respectively (p = 1). Although age was a factor associated with the development of postoperative complications in the univariate regression model (OR 3.81, 95% CI 1.31 to 11.11, p = 0.014), it lost significance after performing the multivariate analysis (OR 2.48, 95% CI 0.78 to 7.90, p = 0.125).

CONCLUSION

The age of 90 years old was not a barrier to perform elective THA safely. Nonagenarians had higher in-hospital minor complications when compared to the younger cohort. However, age over 90 years was not an independent risk factor for unplanned readmissions or mortality. Multimodal protocols of perioperative care are paramount for improving outcomes after THA in very old patients.

Anterior Center-Edge Angle Is Less Reliable Than Anterior Wall Index to Predict Anterior Coverage of the Femoral Head

BACKGROUND

No consensus is available regarding which radiographic measurement most accurately correlates with anterior coverage of the femoral head.

PURPOSE

(1) To determine the correlation between 2 measurements of anterior wall coverage: total anterior coverage (TAC) calculated from radiographs and equatorial anterior acetabular sector angle (eAASA) calculated from computed tomography (CT) scans; (2) to define the correlation between anterior center-edge angle (ACEA) and anterior wall index (AWI) with TAC and eAASA; and (3) to investigate what other radiographic metrics may help predict anterior coverage.

STUDY DESIGN

Cohort study (Diagnosis); Level of evidence, 3.

METHODS

The authors retrospectively reviewed 77 hips (48 patients) for which radiographs and CT scans were obtained for reasons other than hip-related pain. Mean age of the population was 62 ± 22 years; 48 (62%) hips were from female patients. Two observers measured lateral center-edge angle (LCEA), AWI, Tönnis angle, ACEA, CT-based pelvic tilt, and CT-based acetabular version, with all Bland-Altman plots within 95% agreement. Correlation between intermethod measurements was estimated with a Pearson coefficient. Linear regression was used to test the ability of baseline radiographic measurements to predict both TAC and eAASA.

RESULTS

Pearson coefficients were r = 0.164 (ACEA vs TAC; P = .155), r = 0.170 (ACEA vs eAASA; P = .140), r = 0.58 (AWI vs TAC; P = .0001), and r = 0.693 (AWI vs eAASA; P < .0001). Multiple linear regression model 1 showed that AWI (β = 17.8; 95% CI, 5.7 to 29.9; P = .004), CT acetabular version (β = -0.45; 95% CI, -0.71 to -0.22; P = .001), and LCEA (β = 0.33; 95% CI, 0.19 to 0.47; P = .001) were useful to predict TAC. Multiple linear regression model 2 revealed that AWI (β = 25; 95% CI, 15.67 to 34.4; P = .001), CT acetabular version (β = -0.48; 95% CI, -0.67 to -0.29; P = .001), CT pelvic tilt (β = 0.26; 95% CI, 0.12 to 0.4; P = .001), and LCEA (β = 0.21; 95% CI, 0.1 to 0.3; P = .001) accurately predicted eAASA. Model-based estimates and 95% CIs using 2000 bootstrap samples from the original data were 6.16 to 28.6 for AWI in model 1 and 15.1 to 34.26 for AWI in model 2.

CONCLUSION

There was a moderate to strong correlation between AWI and both TAC and eAASA, whereas ACEA correlated weakly with the former measurements, thus not being useful to quantify anterior acetabular coverage. Other variables such as LCEA, acetabular version, and pelvic tilt may also help predict anterior coverage in asymptomatic hips.

Feasibility of total hip arthroplasty in cerebral palsy patients: a systematic review on clinical outcomes and complications

PURPOSE

Total hip arthroplasty (THA) is a successful treatment for hip osteoarthritis secondary to hip dysplasia. However, the reported rate of complications following THA in the settings of neuromuscular diseases is high. This systematic review aimed to analyze the indications, functional outcomes and surgical failures of primary THA in cerebral palsy (CP) patients.

METHODS

MEDLINE, EMBASE and the Cochrane Database of Systematic Reviews were searched, and all clinical studies focusing on THA in patients with CP from inception through March 2020 were included. The methodological quality was assessed with Guo et al.'s quality appraisal checklist for case series and case-control studies, while cohort and prospective studies were evaluated with a modified version of the Downs and Black's quality assessment checklist.

RESULTS

The initial search returned 69 studies out of which 15, including 2732 THAs, met the inclusion criteria. The most frequent indication for THA was dislocated painful hip for which previous non-operative treatment had failed. Complications presented in 10 to 45% of cases. The most frequently reported complication was dislocation (1-20%), followed by component loosening (0.74-20%). Aseptic component loosening was the most frequent cause of revision surgery, followed by dislocation and periprosthetic fracture. Mean implant survival at ten years was 84% (range 81-86%).

CONCLUSION

The available literature suggests that although THA is a beneficial procedure in CP patients, it has a higher rate of complications and worse implant survival than the general population.

Prevention of early complications following total hip replacement

Total hip arthroplasty (THA) has been quoted as "the operation of the century", owing to its efficacy and the substantial improvements evidenced with respect to functional patient outcomes and quality of life. However, early postoperative complications are often inevitable, hence it is imperative to take every step to prevent them and minimise morbidity and mortality. This manuscript focuses on the most common early complications following THA, namely venous thromboembolism (VTE), prosthetic joint infection, periprosthetic fracture, instability, and leg length inequality. It aims to outline effective risk stratification strategies and prevention measures that could apply to the wider Orthopaedic community.

Selected Vancouver B2 periprosthetic femoral fractures around cemented polished femoral components can be safely treated with osteosynthesis

AIMS

We aimed to compare the implant survival, complications, readmissions, and mortality of Vancouver B2 periprosthetic femoral fractures (PFFs) treated with internal fixation with that of B1 PFFs treated with internal fixation and B2 fractures treated with revision arthroplasty.

METHODS

We retrospectively reviewed the data of 112 PFFs, of which 47 (42%) B1 and 27 (24%) B2 PFFs were treated with internal fixation, whereas 38 (34%) B2 fractures underwent revision arthroplasty. Decision to perform internal fixation for B2 PFFs was based on specific radiological (polished femoral components, intact bone-cement interface) and clinical criteria (low-demand patient). Median follow-up was 36.4 months (24 to 60). Implant survival and mortality over time were estimated with the Kaplan-Meier method. Adverse events (measured with a modified Dindo-Clavien classification) and 90-day readmissions were additionally compared between groups.

RESULTS

In all, nine (8.01%) surgical failures were detected. All failures occurred within the first 24 months following surgery. The 24-month implant survival was 95.4% (95% confidence interval (CI) 89.13 to 100) for B1 fractures treated with internal fixation, 90% (95% CI 76.86 to 100) for B2 PFFs treated with osteosynthesis-only, and 85.8% (95% CI 74.24 to 97.36) for B2 fractures treated with revision THA, without significant differences between groups (p = 0.296). Readmissions and major adverse events including mortality were overall high, but similar between groups (p > 0.05). The two-year patient survival rate was 87.1% (95% CI 77.49 to 95.76), 66.7% (95% CI 48.86 to 84.53), and 84.2% (95% CI 72.63 to 95.76), for the B1 group, B2 osteosynthesis group, and B2 revision group, respectively (p = 0.102).

CONCLUSION

Implant survival in Vancouver B2 PFFs treated with internal fixation was similar to that of B1 fractures treated with the same method and to B2 PFFs treated with revision arthroplasty. Low-demand, elderly patients with B2 fractures around well-cemented polished femoral components with an intact bone-cement interface can be safely treated with internal fixation. Cite this article: Bone Joint J 2021;103-B(7):1222-1230.

One-stage exchange should be avoided in periprosthetic joint infection cases with massive femoral bone loss or with history of any failed revision to treat periprosthetic joint infection

AIMS

There is a paucity of long-term studies analyzing risk factors for failure after single-stage revision for periprosthetic joint infection (PJI) following total hip arthroplasty (THA). We report the mid- to long-term septic and non-septic failure rate of single-stage revision for PJI after THA.

METHODS

We retrospectively reviewed 88 cases which met the Musculoskeletal Infection Society (MSIS) criteria for PJI. Mean follow-up was seven years (1 to 14). Septic failure was diagnosed with a Delphi-based consensus definition. Any reoperation for mechanical causes in the absence of evidence of infection was considered as non-septic failure. A competing risk regression model was used to evaluate factors associated with septic and non-septic failures. A Kaplan-Meier estimate was used to analyze mortality.

RESULTS

The cumulative incidence of septic failure was 8% (95% confidence interval (CI) 3.5 to 15) at one year, 13.8% (95% CI 7.6 to 22) at two years, and 19.7% (95% CI 12 to 28.6) at five and ten years of follow-up. A femoral bone defect worse than Paprosky IIIA (hazard ratio (HR) 13.58 (95% CI 4.86 to 37.93); p < 0.001) and obesity (BMI ≥ 30 kg/m²; HR 3.88 (95% CI 1.49 to 10.09); p = 0.005) were significantly associated with septic failure. Instability and periprosthetic fracture were the most common reasons for mechanical failure (5.7% and 4.5%, respectively). The cumulative incidence of aseptic failure was 2% (95% CI 0.4 to 7) at two years, 9% (95% CI 4 to 17) at five years, and 12% (95% CI 5 to 22) at ten years. A previous revision to treat PJI was significantly associated with non-septic failure (HR 9.93 (95% CI 1.77 to 55.46); p = 0.009). At the five-year timepoint, 93% of the patients were alive (95% CI 84% to 96%), which fell to 86% (95% CI 75% to 92%) at ten-year follow-up.

CONCLUSION

Massive femoral bone loss was associated with greater chances of developing a further septic failure. All septic failures occurred within the first five years following the one-stage exchange. Surgeons should be aware of instability and periprosthetic fracture being potential causes of further aseptic revision surgery. Cite this article: Bone Joint J 2021;103-B(7):1247-1253.

Patients with no recurrence of infection five years after two-stage revision hip arthroplasty may be classified as periprosthetic infection 'in remission'

AIMS

We aimed to report the mid- to long-term rates of septic and aseptic failure after two-stage revision surgery for periprosthetic joint infection (PJI) following total hip arthroplasty (THA).

METHODS

We retrospectively reviewed 96 cases which met the Musculoskeletal Infection Society criteria for PJI. The mean follow-up was 90 months (SD 32). Septic failure was assessed using a Delphi-based consensus definition. Any further surgery undertaken for aseptic mechanical causes was considered as aseptic failure. The cumulative incidence with competing risk analysis was used to predict the risk of septic failure. A regression model was used to evaluate factors associated with septic failure. The cumulative incidence of aseptic failure was also analyzed.

RESULTS

There were 23 septic failures at final follow-up, with a cumulative incidence of 14% (95% confidence interval (CI) 8% to 22%) at one year, 18% (95% CI 11% to 27%) at two years, 22% (95% CI 14% to 31%) at five years, and 23% (95% CI 15% to 33%) at ten years. Having at least one positive culture (hazard ratio (HR) 2.38 (interquartile range (IQR) 1.19 to 4.74); p = 0.013), or a positive intraoperative frozen section (HR 2.55 (IQR 1.06 to 6.15); p = 0.037) was significantly associated with septic failure after reimplantation. With dislocation being the most common cause of aseptic revision (5.2%), the cumulative incidence of aseptic failure was 1% (95% CI 0% to 5%) at one year, 6% (95% CI 1% to 8%) at five years, and 8% (95%CI 3% to 17%) at ten years.

CONCLUSION

If there is no recurrent infection in the five years following reimplantation, the chances of further infection thereafter are remote. While the results of a frozen section may be a reliable guide to the timing of reimplantation, intraoperative culture has, currently, only prognostic value. Surgeons should be aware that instability remains a potential indication for further revision surgery. Cite this article: Bone Joint J 2021;103-B(1):79-86.

International Organism Profile of Periprosthetic Total Hip and Knee Infections

BACKGROUND

There is scarce literature describing pathogens responsible for periprosthetic joint infections (PJIs) around the world. Therefore, we sought to describe periprosthetic joint infection causative organisms, rates of resistant organisms, and polymicrobial infections at 7 large institutions located in North/South America and Europe.

METHODS

We performed a retrospective study of 654 periprosthetic hip (n = 361) and knee (n = 293) infections (January 2006 to October 2019) identified at Cleveland Clinic Ohio/Florida in the United States (US) (n = 159), Hospital Italiano de Buenos Aires in Argentina (n = 99), Hospital Asociación Española in Uruguay (n = 130), Guy's and St Thomas' Hospital in the United Kingdom (UK) (n = 103), HELIOS Klinikum in Germany (n = 59), and Vreden Institute for Orthopedics in St. Petersburg, Russia (n = 104). Analyses were performed for the entire cohort, knees, and hips. Alpha was set at 0.05.

RESULTS

Overall, the most frequent organisms identified were Staphylococcus aureus (24.8%) and Staphylococcus epidermidis (21.7%). The incidence of organisms resistant to at least one antibiotic was 58% and there was a significant difference between hips (62.3%) and knees (52.6%) (P = .014). Rates of resistant organisms among countries were 37.7% (US), 66.7% (Argentina), 71.5% (Uruguay), 40.8% (UK), 62.7% (Germany), and 77.9% (Russia) (P < .001). The overall incidence of polymicrobial infections was 9.3% and the rates across nations were 9.4% in the US, 11.1% in Argentina, 4.6% in Uruguay, 4.9% in UK, 11.9% in Germany, and 16.3% in Russia (P = .026).

CONCLUSION

In the evaluated institutions, S aureus and S epidermidis accounted for almost 50% of all infections. The US and the UK had the lowest incidence of resistant organisms while Germany and Russia had the highest. The UK and Uruguay had the lowest rates of polymicrobial infections.

4- to 8-year complication analysis of 2 'partial collum' femoral stems in primary THA

OBJECTIVES

Compare the clinical and radiological outcome of CFP stem with the MiniHip design in a prospective series, with special interest in intraoperative periprosthetic fracture (IPPF).

METHODS

We prospectively followed 101 cases treated with the MiniHip stem (Group 1) and 89 with the CFP stem (Group 2) operated between 2010 and 2014. No significant demographic differences were observed between both groups. Median follow-up was 72 months. Average stem length was 41% shorter in the MiniHip group (p < 0.001). Radiological parameters were measured and a logistcic regression model was created to evaluate factors associated with IPPF.

RESULTS

Mean mHHS improved from 54 to 95 in the MiniHip group (p < 0.001) and from 64 to 98 in the CFP group (p < 0.001). No significant differences were observed in terms of loosening, infection or instability. We observed 7 IPPFs (3.68%), 3 in group 1 and 4 in group 2. After adjusting for confounders, CFP was not associated with a greater risk of IPPF (OR 3.23; 95% CI, 0.250-42.034, p = 0.368), however, a more complex fracture pattern was observed with this stem design. Prior acetabular fractures were associated with IPPF (OR 66.85; 95% CI, 1.142-3911, p = 0.043). Compared to Dorr A femurs, type Dorr B appeared protective against IPPF (OR 0.039; 95% CI, 0.001-1.109, p = 0.058). Valgus alignment tended to increase the risk of IPPF (OR 20.59; 95% CI 0.870-487.221, p = 0.061).

CONCLUSIONS

MiniHip showed similar radiological outcomes to CFP at short- to mid-term follow-up without increasing IPPFs with a shorter stem length. Given that CFP produced a more complex IPPF pattern, surgeons should be cautious with alignment of this particular design, especially in Dorr A femur.

Hip preservation surgery and the acetabular fossa

As our understanding of hip function and disease improves, it is evident that the acetabular fossa has received little attention, despite it comprising over half of the acetabulum’s surface area and showing the first signs of degeneration. The fossa’s function is expected to be more than augmenting static stability with the ligamentum teres and being a templating landmark in arthroplasty. Indeed, the fossa, which is almost mature at 16 weeks of intrauterine development, plays a key role in hip development, enabling its nutrition through vascularization and synovial fluid, as well as the influx of chondrogenic stem/progenitor cells that build articular cartilage. The pulvinar, a fibrofatty tissue in the fossa, has the same developmental origin as the synovium and articular cartilage and is a biologically active area. Its unique anatomy allows for homogeneous distribution of the axial loads into the joint. It is composed of intra-articular adipose tissue (IAAT), which has adipocytes, fibroblasts, leucocytes, and abundant mast cells, which participate in the inflammatory cascade after an insult to the joint. Hence, the fossa and pulvinar should be considered in decision-making and surgical outcomes in hip preservation surgery, not only for their size, shape, and extent, but also for their biological capacity as a source of cytokines, immune cells, and chondrogenic stem cells.

Cite this article: Bone Joint Res 2020;9(12):857–869.

Hypovitaminosis D in lower extremity Joint Arthroplasty: A systematic review and meta-analysis

The purpose of the current systematic review was to identify the prevalence of hypovitaminosis-D in LE-TJA patients; and outline the association between pre-operative hypovitaminosis and post-operative outcomes. A search of PubMed-Medline and the Cochrane-Library databases was performed for literature published before November 27th, 2019. The eighteen studies analyzed had a pooled prevalence for vitamin D insufficiency (20 - <30 ng/mL) and deficiency (<20 ng/mL) of 53.4% and 39.4%, respectively. Hypovitaminosis-D was associated with higher complication rates (p = 0.043), and a greater prevalence among septic versus aseptic revisions (p = 0.016). Therefore, pre-operative screening for hypovitaminosis-D can be beneficial in patients undergoing LE-TJA.

LEVEL OF EVIDENCE

Systematic Review (Level III).

Preparation for the next COVID-19 wave: The European Hip Society and European Knee Associates recommendations

PURPOSE

To plan for the continuance of elective hip and knee arthroplasty during a resurgence or new wave of COVID-19 infections.

METHOD

A systematic review was conducted using the terms "COVID-19" or "SARS-Cov-2" and "second wave". No relevant citations were found to inform on recommendations the plan. Therefore, an expert panel of the European Hip Society and the European Knee Associates was formed to provide the recommendations.

RESULTS

Overall, the recommendations consider three phases; review of the first wave, preparation for the next wave, and during the next wave. International and national policies will drive most of the management. The recommendations focus on the preparation phase and, in particular, the actions that the individual surgeon needs to undertake to continue with, and practice, elective arthroplasty during the next wave, as well as planning their personal and their family's lives. The recommendations expect rigorous data collection during the next wave, so that a cycle of continuous improvement is created to take account of any future waves.

CONCLUSIONS

The recommendations for planning to continue elective hip and knee arthroplasty during a new phase of the SARS-Cov-2 pandemic provide a framework to reduce the risk of a complete shutdown of elective surgery. This involves engaging with hospital managers and other specialities in the planning process. Individuals have responsibilities to themselves, their colleagues, and their families, beyond the actual delivery of elective arthroplasty.

Is hip arthroscopy useful in the treatment of borderline dysplasia?: a case-control study

INTRODUCTION

Since arthroscopy remains a controversial treatment of hip dysplasia, our objective was to analyse its clinical and radiological results in a cohort of patients with dysplasia and compare them to controls with femoroacetabular impingement (FAI).

MATERIAL AND METHODS

We retrospectively analysed a series of patients who underwent hip arthroscopy for the treatment of labral pathology; 29 of them with borderline hip dysplasia and 197 with FAI, comparing reoperations and joint survival. The diagnosis of borderline dysplasia was made with a lateral centre-edge angle greater than 18° but less than 25°. The average follow-up was 43 months. We performed a multivariate regression analysis to evaluate the association of reoperations with different demographic, radiological and intraoperative variables.

RESULTS

Seven complications were registered in the FAI group (1 medically treated superficial wound infection, 3 pudendal nerve paraesthesias, 1 deep vein thrombosis and 2 heterotopic ossifications) and none in the dysplasia group. While 5 patients from the FAI group required a new surgery, none of the dysplasia group was re-operated (p=.38). After adjusting for confounders, reoperation showed a very strong association with the finding of osteochondral lesions during index surgery, with a coefficient of .12 (p<.001, 95%CI=.06-.17).

CONCLUSION

Hip arthroscopy was useful in the treatment of borderline dysplasia, without non-inferior survival compared to the FAI group. We suggest indicating it carefully in dysplasia cases, whenever the symptoms of femoroacetabular friction prevail over those of instability.

Prolonged social lockdown during COVID-19 pandemic and hip fracture epidemiology

Purpose

To analyse the impact of prolonged mandatory lockdown due to COVID-19 on hip fracture epidemiology.

Methods

Retrospective case-control study of 160 hip fractures operated upon between December 2019 and May 2020. Based on the date of declaration of national lockdown, the cohort was separated into two groups: ‘pre-COVID time’ (PCT), including 86 patients, and ‘COVID time’ (CT), consisting of 74 patients. All CT patients tested negative for SARS-CoV-2. Patients were stratified based on demographic characteristics. Outcome measures were 30-day complications, readmissions and mortality. A logistic regression model was run to evaluate factors associated with mortality.

Results

Age, female/male ratio, body mass index and American Society of Anaesthesia score were similar between both groups (p > 0.05). CT patients had a higher percentage of Charlson ≥ 5 and Rockwood Frailty Index ≥ 5 scores (p < 0.05) as well as lower UCLA and Instrumental Activities of Daily Living scores (p < 0.05). This translated into a higher hemiarthroplasty/total hip arthroplasty ratio during CT (p = 0.04). Thromboembolic disease was higher during CT (p = 0.02). Readmissions (all negative for SARS-CoV-2) were similar between both groups (p = 0.34). Eight (10.8%) casualties were detected in the CT group, whereas no deaths were seen in the control group. Logistic regression showed that frailer (p = 0.006, OR 10.46, 95%CI 8.95–16.1), less active (p = 0.018, OR 2.45, 95%CI 1.45–2.72) and those with a thromboembolic event (p = 0.005, OR 30, 95%CI 11–42) had a higher risk of mortality.

Conclusion

Despite testing negative for SARS-CoV-2, CT patients were less active and frailer than PCT patients, depicting an epidemiological shift that was associated with higher mortality rate.

State-of-the-art diagnosis and surgical treatment of acute peri-prosthetic joint infection following primary total hip arthroplasty

Acute peri-prosthetic joint infection (PJI) following total hip arthroplasty (THA) is a potentially devastating and undesired complication, with a prevalence of 0.3% to 2.9%. Its suspicion begins with a meticulous physical examination and anamnesis. Diagnosis should be made on the basis of the Musculoskeletal Infection Society criteria. Serum and synovial biomarkers are very useful tools when major criteria are absent.Although sometimes not possible due to medical conditions, surgery is usually the first line of treatment. Although its outcome is highly correlated with the isolated microorganism, irrigation and debridement with implant retention (DAIR) is the gold standard for treatment. Ideally, the prior approach should be proximally and distally extended to augment the field of view and remove all of the prosthetic modular components, that is, femoral head and acetabular insert.Given DAIR's unclear control of infection, with successful outcomes in the range of 30% to 95%, one- or two-stage revision protocols may play a role in certain cases of acute infections; nonetheless, further prospective, randomized studies are necessary to compare long-term outcomes between DAIR and revision surgeries.Following surgical treatment, length of antibiotherapy is in the range of six weeks to six months, without any difference in outcomes between short and long protocols. Treatment should be adjusted to the isolated bacteria and controlled further with post-operative serum biomarker levels. Cite this article: EFORT Open Rev 2018;3:434-441. DOI: 10.1302/2058-5241.3.170032.

No lower bacterial adhesion for ceramics compared to other biomaterials: An in vitro analysis

BACKGROUND

Although there is some clinical evidence of ceramic bearings being associated with a lower infection rate after total hip arthroplasty (THA), available data remains controversial since this surface is usually reserved for young, healthy patients. Therefore, we investigated the influence of five commonly used biomaterials on the adhesion potential of four biofilm-producing bacteria usually detected in infected THAs.

HYPOTHESIS

Ceramic biomaterials exhibit less bacterial adherence than other biomaterials.

MATERIAL AND METHODS

In this in vitro research, we evaluated the ability of Staphylococcus aureus, Staphylococcus epidermidis ATCC 35984, Escherichia coli ATCC 25922 and Pseudomonas aeruginosa to adhere to the surface of a cobalt-chromium metal head, a fourth-generation ceramic head, a fourth-generation ceramic insert, a highly-crossed linked polyethylene insert and a titanium porous-coated acetabular component. After an initial washing step, bacterial separation from the surface of each specimen was done with a vortex agitator. The colony-forming units were counted to determine the number of viable adherent bacteria.

RESULTS

We found no differences on global bacterial adhesion between the different surfaces (p=0.5). E. coli presented the least adherence potential among the analysed pathogens (p<0.001). The combination of E. coli and S. epidermidis generated an antagonist effect over the adherence potential of S. epidermidis individually (58±4% vs. 48±5%; p=0.007). The combination of P. aeruginosa and S. aureus presented a trend to an increased adherence of P. aeruginosa independently, suggesting an agonist effect (71% vs. 62%; p=0.07).

DISCUSSION

Ceramic bearings appeared not to be related to a lower bacterial adhesion than other biomaterials. However, different adhesive potentials among bacteria may play a major role on infection's inception.

LEVEL OF EVIDENCE

IV, in vitro study.

Transfusion rate using intravenous tranexamic acid in hip revision surgery

INTRODUCTION

Hip revision surgery is associated with a high probability of the necessity for a blood transfusion. Different studies support the use of tranexamic acid (TXA) to decrease the rate of transfusions in primary hip surgery. Nevertheless, the use of this drug in hip revision surgery has not yet been widely accepted. The aim of our study was to establish the rate of blood transfusion with and without TXA in hip revision surgery.

METHODS

We retrospectively studied 125 hip revision surgery patients operated on between 2011 and 2014. We divided our series into 2 groups: the TXA group with 61 patients (in which a 1000 mg dose of TXA was used before the skin incision and a second identical dose after skin closure) and a control group with 64 patients. We analysed the red blood cell (RBC) transfusion rates and their odds risk as well as the presence of collateral complications.

RESULTS

Average RBC transfusion was 2.7 units/patient (range 0-6) in the control group compared to 1.6 units/patient (range 0-6) in the TXA group. A 90.11% (odds ratio [OR] 0.098; confidence interval [CI] 0.02-0.04; p<0.0029) odds risk reduction for transfusion of at least 1 unit of erythrocyte blood cell was observed in the TXA group. Complications associated with the TXA were similar in both groups.

INTERPRETATION

The benefits of TXA have been shown in elective hip replacement. In this study, TXA proved to be safe and efficacious in reducing the need for transfusions following revision total hip arthroplasty.

Influence of single-dose intravenous tranexamic acid on total hip replacement : A study on transfusions, collateral complications, and readmissions

INTRODUCTION

To determine the effects of tranexamic acid (TXA) on transfusions in patients undergoing hip replacement with a hybrid or cementless prosthesis.

METHODS

A group of 172 consecutive patients aged 18 years or older who underwent elective hip replacement with uncemented or hybrid prostheses, undergoing surgery between January 2012 and January 2014 by the same primary surgeon and anesthesiologist, were retrospectively included. TXA (1 g) was administered immediately before incision in the TXA group. Primary variables included number of red blood cell transfusions and the influence of TXA for each type of prosthesis. Secondary variables included hematocrit at discharge, length of hospital stay, thrombosis or pulmonary embolism, seizures, and death.

RESULTS

Average transfusion was 1.53 units/patient in the control group compared to 0.6 units/patient in the TXA group (z = 6.29; U = 1640.5; p < 0.0001). TXA use was significantly correlated with the number of units transfused (p < 0.0001, 95% CI -1.24 to -0.68). Odds risk reduction for transfusion was observed during surgery (OR: 0.14; CI 0.06-0.29; p < 0.0001) and during the rest of hospital stay (OR: 0.11; CI 0.01-0.96; p = 0.046). Both hybrid and cementless prostheses that received TXA were transfused less than control groups (0.57 ± 1 vs. 1.7 ± 1 p < 0.01 and 0.65 ± 1 vs. 1.24 ± 1 p < 0.01). No difference was observed between the groups regarding adverse effects. Hematocrit values at discharge and length of hospital stay were similar between groups. No deaths were observed during hospital stay.

CONCLUSIONS

TXA reduced transfusions without increasing the prevalence of adverse effects. This reduction was observed during surgery and the following days of hospital stay for both for hybrid and cementless prosthesis.

Metaphyseal debonding of the Corail collarless cementless stem: report of 18 cases and case-control study

AIMS

The Corail stem has good long-term results. After four years of using this stem, we have detected a small group of patients who have presented with symptomatic metaphyseal debonding. The aim of this study was to quantify the incidence of this complication, to delineate the characteristics of patients presenting with this complication and to compare these patients with asymptomatic controls to determine any important predisposing factors.

PATIENTS AND METHODS

Of 855 Corail collarless cementless stems implanted for osteoarthritis, 18 presented with symptomatic metaphyseal debonding. A control group of 74 randomly selected patients was assembled. Clinical and radiological parameters were measured and a logistic regression model was created to evaluate factors associated with metaphyseal debonding.

RESULTS

The prevalence of this complication was 2.1% in our series. In the multivariable model, the presence of a Dorr B-type proximal femur was associated with metaphyseal debonding (odds ratio (OR) 10.73, 95% confidence interval (CI) 2.31 to 49.97, p = 0.002), as was a body mass index > 25 kg/m² (OR 6.85, 95% CI 1.06 to 44.28, p = 0.04). Smaller stems and the use of a polyethylene acetabular liner appeared to be protective when compared with metal and ceramic setting hard-on-hard bearings.

CONCLUSION

We have described an uncommon but important mode of failure of the Corail stem. Surgeons should be aware of this phenomenon; overweight patients with Dorr B-type femurs and in whom hard bearings are used appear to be particularly at risk. Cite this article: Bone Joint J 2017;99-B:1435-41.

Transfusion rate using intravenous tranexamic acid in hip revision surgery

INTRODUCTION

Hip revision surgery is associated with a high probability of the necessity for a blood transfusion. Different studies support the use of tranexamic acid (TXA) to decrease the rate of transfusions in primary hip surgery. Nevertheless, the use of this drug in hip revision surgery has not yet been widely accepted. The aim of our study was to establish the rate of blood transfusion with and without TXA in hip revision surgery.

METHODS

We retrospectively studied 125 hip revision surgery patients operated on between 2011 and 2014. We divided our series into 2 groups: the TXA group with 61 patients (in which a 1000 mg dose of TXA was used before the skin incision and a second identical dose after skin closure) and a control group with 64 patients. We analysed the red blood cell (RBC) transfusion rates and their odds risk as well as the presence of collateral complications.

RESULTS

Average RBC transfusion was 2.7 units/patient (range 0-6) in the control group compared to 1.6 units/patient (range 0-6) in the TXA group. A 90.11% (odds ratio [OR] 0.098; confidence interval [CI] 0.02-0.04; p<0.0029) odds risk reduction for transfusion of at least 1 unit of erythrocyte blood cell was observed in the TXA group. Complications associated with the TXA were similar in both groups.

INTERPRETATION

The benefits of TXA have been shown in elective hip replacement. In this study, TXA proved to be safe and efficacious in reducing the need for transfusions following revision total hip arthroplasty.

Arthroscopic acetabuloplasty without labral detachment for focal pincer-type impingement: a minimum 2-year follow-up

In order to access and resect the acetabular rim, arthroscopic acetabuloplasty was described with labral detachment. When the chondrolabral junction remains intact, acetabuloplasty and labral refixation can be performed maintaining an unharmed labrum. We aimed to evaluate the outcome of a group of patients treated with arthroscopic acetabuloplasty without labral detachment. During the study period, we retrospectively analysed 44 patients with pincer-type o combined impingement and an intact chondroblabral junction, with an average follow-up of 32 months (range: 27-38). We excluded patients with isolated CAM-type impingement and previous hip pathology. Radiographs were analysed to define impingement and classify grade of osteoarthritis. Clinical evaluation consisted of pre-operative and post-operative modified Harris hip score (mHHS) and WOMAC as well as post-operative visual analogue scale (VAS) of pain and satisfaction. Reoperations were considered surgical failures for purposes of survival analysis. Mean mHHS changed from 51.06 (SD 4.81) pre-operatively to 84.97 (SD 12.79) post-operatively. Pre-operative WOMAC was 29.18 (SD 8) and post-operative, 13.10 (SD 11). Post-operative VAS was 7.5 and 2.27 for satisfaction and pain, respectively. When comparing patients with Tönnis 0 to those with Tönnis 1, the former showed better results regarding post-operative mHHS (89.9 s versus 77.85, P = 0.03), pain VAS (1.5 versus 6.3, P = 0.03) and satisfaction VAS (8.2 versus 6.3, P = 0.01). Survival was 100% at 24 months and 76% at 40 months (95% CI: 35-98%). Arthroscopic acetabuloplasty without labral detachment achieved good clinical outcomes. Slight degenerative changes on radiographs correlated with poorer clinical outcomes.

Primary Total Hip Arthroplasty With Fourth-Generation Ceramic-on-Ceramic: Analysis of Complications in 939 Consecutive Cases Followed for 2-10 Years

BACKGROUND

Delta ceramics may be the bearing of choice for younger and active patients due to its improved toughness and wear characteristics, provided there is no risk of fracture. However, ceramic fracture is the most serious complication related to this type of bearing. Although millions of Delta ceramics have been implanted worldwide, short to midterm results have been scarcely reported in the literature. The purpose of this study was to report the complication rate at short to midterm follow-up associated with the bearing surface used in a series of primary total hip arthroplasties with Delta ceramic-on-ceramic bearings performed in a single institution.

METHODS

A total of 939 cases (880 patients) undergoing primary total hip arthroplasty with fourth-generation Delta ceramic-on-ceramic bearings were retrospectively reviewed. They were followed for an average of 5.3 years (2-10 years).

RESULTS

One hip experienced a liner fracture, 2 cups presented early loosening due to friction between the acetabular screw and the backside of the liner, one femoral ball head had a fracture; one case of squeaking was reported, which is impending revision. Considering revision or impending revision in relationship with the bearing surface as the end point, the mean survival rate was 99.3% (confidence interval 95%, 98.3%-99.7%) at 2-10 years.

CONCLUSION

This study showed a low rate of ceramic fracture compared with others; however, it was much higher than the complication rate presented by the manufacturers. The complications observed were directly related to technical errors that surgeons should avoid when using this type of surface.

Intraoperative synovial C-reactive protein is as useful as frozen section to detect periprosthetic hip infection

BACKGROUND

Synovial quantification of C-reactive protein (SCRP) has been recently published with high sensitivity and specificity in the diagnosis of periprosthetic joint infection. However, to our knowledge, no studies have compared the use of this test with intraoperative frozen section, which is considered by many to be the best intraoperative test now available.

QUESTIONS/PURPOSES

We asked whether intraoperative SCRP could lead to comparable sensitivity, specificity, and predictive values as intraoperative frozen section in revision total hip arthroplasty.

METHODS

A prospective study was performed including 76 patients who underwent hip revision for any cause. SCRP quantification (using 9.5 mg/L as denoting infection) and the analysis of frozen section of intraoperative samples (five or more polymorphonuclear leukocytes under high magnification in 10 fields) were performed in all the patients. The definitive diagnosis of an infection was determined according to the Musculoskeletal Infection Society (MSIS). In this group, 30% of the patients were diagnosed with infection using the MSIS criteria (23 of 76 patients).

RESULTS

With the numbers available, there were no differences between SCRP and frozen section in terms of their ability to diagnose infection. The sensitivity of SCRP was 90% (95% confidence interval [CI], 70.8%-98.6%), the specificity was 94% (95% CI, 84.5%-98.7%), the positive predictive value was 87% (95% CI, 66.3%-97%), and the negative predictive value was 96% (95% CI, 87%-99.4%); the sensitivity, specificity, positive predictive value, and negative predictive value were the same using frozen sections to diagnose infection. The positive likelihood ratio was 16.36 (95% CI, 5.4-49.5), indicating a low probability of an individual without the condition having a positive test, and the negative likelihood ratio was 0.10 (95% CI, 0.03-0.36), indicating low probability of an individual without the condition having a negative test.

CONCLUSIONS

We found that quantitative SCRP had similar diagnostic value as intraoperative frozen section with comparable sensitivity, specificity, and predictive value in a group of patients undergoing revision total hip arthroplasty. In our institution, SCRP is easier to obtain, less expensive, and less dependent on the technique of obtaining and interpreting a frozen section. If our findings are confirmed by other groups, we suggest that quantitative SCRP be considered as a viable alternative to frozen section.

LEVEL OF EVIDENCE

Level I, diagnostic study.

High failure rate with the GAP II ring and impacted allograft bone in severe acetabular defects

BACKGROUND

Reconstruction rings and bone allografts have been proposed to manage severe acetabular bone loss. However, a high early failure rate of the Graft Augmentation Prosthesis (GAP) II reinforcement ring (Stryker Orthopaedics, Mahwah, NJ, USA) has been reported in one small series.

QUESTIONS/PURPOSES

We therefore determined (1) the survival of this device in combination with impacted morselized allograft bone in patients with severe defects and (2) the complication rate.

METHODS

We retrospectively reviewed 24 patients (21 aseptic and three septic) with severe acetabular bone loss (10 hips with Type III defects and 14 with Type IV defects according to the American Academy of Orthopaedic Surgeons classification). We determined function and numbers of failures. The minimum followup was 24 months (mean, 34 months; range, 24-72 months).

RESULTS

At latest followup, the reconstruction had failed in nine of the 24 patients: six with aseptic loosening, three with infection. The average postoperative Merle d'Aubigné-Postel score of the patients whose reconstructions had not failed was 16.6 points; at latest followup, these patients had radiographic evidence of incorporation and consolidation of bone allografts. Seven of the nine patients whose reconstructions had failed underwent reoperation. Fatigue fracture of the ring at the plate-cup union occurred in five patients at an average of 45 months postoperatively. All patients with failed reconstructions who underwent reoperation were treated with Trabecular Metal(™) (Zimmer Inc, Warsaw, IN, USA) cups and were functioning well at latest followup.

CONCLUSIONS

We observed a high rate (37%) of early catastrophic failures of the GAP II reconstruction ring, particularly in patients with Type IV defects. Due to this high failure rate, we have abandoned its use.

LEVEL OF EVIDENCE

Level IV, therapeutic study. See the Instructions for Authors for a complete description of levels of evidence.

Squeaking in a Delta ceramic-on-ceramic uncemented total hip arthroplasty

Squeaking is one of the main concerns related to the use of ceramic-on-ceramic total hip arthroplasty. Although it has received much recent publicity, most of the previous reports on this complication have been related to the use of the second generation of alumina ceramics combined with a cup having an elevated metal rim to protect the ceramic liner from neck impingement. We report a patient with a third-generation Biolox Delta (CeramTec AG, Plochingen, Germany) ceramic-on-ceramic uncemented total hip arthroplasty without an elevated metal rim in the cup who presented with a squeaking hip at 23 months postoperative. Although this complication was mainly related to a specific design in the literature, this case demonstrates that newer generation of ceramics can also present squeaking.

Incidence of deep infection in aseptic revision THA using vancomycin-impregnated impacted bone allograft

The addition of antibiotic to cement is a frequent practice in aseptic revision hip surgery There is concern about adding vancomycin to cement due to potential effects on mechanical properties and prolonged elution of subtherapeutic levels antibiotic. Bone allografts can store and provide high levels of vancomycin to surrounding tissues. We analyzed the incidence of infection after one-stage aseptic revision hip reconstruction utilizing acetabular and/or femoral vancomycin-impregnated impacted bone allograft and a THA fixed with cement containing no antibiotic. We hypothesized that the infection rate may be similar to that reported in the literature following traditional impaction grafting using antibiotic loaded cement. Seventy five consecutive patients (80 hips) with a preoperative Merle D'Aubigné and Postel functional score averaging 4.8 points were followed up for a mean of 36 months (range 24 - 59 months). The incidence of infection was 1.25% (CI 95%=96.26-100%). A deep infection (thought to be haematognous in origin) occurred in 1 patient 2 years after the index surgery. The average postoperative Merle D´Aubigne score was 16.2 points. The last radiographic evaluation demonstrated a less than 5 mm acetabular migration and a less than 5 mm femoral subsidence in all cases. Vancomycin-supplemented allografts restored bone stock and provided sound fixation with a low incidence of infection. This incidence of deep sepsis is similar to that reported with antibiotic-loaded PMMA but without the reported mechanical and pharmacological disadvantages.

Combining C-reactive protein and interleukin-6 may be useful to detect periprosthetic hip infection

BACKGROUND

The sensitivity and specificity to detect periprosthetic infection of the different methods have been questioned, and no single laboratory test accurately detects infection before revision arthroplasty.

QUESTIONS/PURPOSES

We asked whether preoperative C-reactive protein (CRP) and interleukin-6 (IL-6) could lead to similar sensitivity, specificity, and predictive values as our previous results obtained with intraoperative frozen section (FS) in revision total hip arthroplasty (THA).

METHODS

We prospectively followed 69 patients who had undergone revision THA for failure of a primary THA. The definitive diagnosis of an infection was determined on the basis of positive histopathologic evidence of infection or growth of bacteria on culture.

RESULTS

Eleven of the 69 hips were infected. The combination of an elevated CRP and IL-6 was correlated with deep infection in all the cases and showed a sensitivity of 0.57 (0.13-1.00), a specificity of 1.00 (0.99-1.00), a positive predictive value of 1.00 (0.87-1.00), and a negative predictive value of 0.94 (0.87-1.00). FS showed a sensitivity of 0.81 (0.54-1.00), a specificity of 0.98 (0.94-1.00), a positive predictive value of 0.90 (0.66-1.00), and a negative predictive value of 0.96 (0.91-1.00). Combining CRP and IL-6 provided similar sensitivity, specificity, and positive predictive values as the FSs.

CONCLUSIONS

Our data suggest the combination of CRP and IL-6 would be a useful serologic tool to complement others when diagnosing periprosthetic infection.

Impacted bone allografts and a cemented stem after failure of an uncemented stem: preliminary results

We reviewed the results of impaction bone grafting technique and a cemented stem in 27 consecutive patients with a failed uncemented femoral component. At an average follow-up of 55 months (25 to 94) none of the femoral components were removed or revised because of aseptic loosening or deep infection. In one hip a non progressive radiolucent line was observed in Gruen zone 5 with no clinical evidence of failure. The average postoperative Merle d'Aubigné and Postel Hip Score was 5.8 points for pain, 5.5 points for mobility and 5.4 points for gait. Revision of a failed uncemented stem with impaction grafting technique provided pain relief and improved function. The rate of success and restoration of bone stock were encouraging at mid-term follow-up.

Incorporation of vancomycin-supplemented bone allograftsRadiographical, histopathological and immunohistochemical study in pigs

We compared the incorporation of bone allografts with or without vancomycin in tibial defects of 18 pigs. High-quality radiographs, histological examination, immunological expression of metalloproteinase-13 (MMP-13) and transforming growth factor-beta 2 (TGFbeta2) indicated that there was no significant difference in bone allograft incorporation between up to 220 times the MIC (minimum inhibitory concentration) in bone allografts with 1 g of vancomycin in each 300 g of allograft or without this supplement.

Nodular skin metastasis mimicking infection in a revision total hip arthroplasty scar

We present the case of a 60-year-old man who had metastasis of a nodular squamous cell carcinoma from a laryngeal carcinoma that mimicked an infected sinus in a 4-month postoperative revision total hip arthroplasty scar. A diagnosis was made at the time of frozen section. The patient died 3 months after tumor resection as a result of multiorgan failure. Nodular squamous cell carcinoma metastasis in a total hip arthroplasty scar is extremely uncommon. However, this association must be considered in a patient with a known tumor after revision surgery. In such patients, we recommend obtaining an intraoperative frozen section to avoid misdiagnosis in cases of infected sinuses associated with implants.

Locking compression plate fixation of Vancouver type-B1 periprosthetic femoral fractures

BACKGROUND

Fractures occurring at or near the distal tip of a hip prosthesis with a stable femoral stem (Vancouver type-B fractures) are associated with many complications because of the inherently unstable fracture pattern. Locking compression plates use screws that lock into the plate allowing multiple points of unicortical fixation. Such unicortical fixation may lower the risk of damage to the cement mantle or a stable femoral stem during the treatment of a periprosthetic femoral fracture. The purpose of this study was to analyze clinically and radiographically a group of patients with a Vancouver type-B1 periprosthetic femoral fracture treated with open reduction and internal fixation with use of a locking compression plate.

METHODS

Fourteen consecutive patients (fourteen hips) with a Vancouver type-B1 periprosthetic femoral fracture were treated with a locking compression plate. There were five men and nine women with an average age of sixty-eight years at the time of fracture. All of the fractures occurred after a total hip arthroplasty performed with cement, and eleven of the arthroplasties were revisions. In addition to the plate, cortical strut allografts were used to stabilize five fractures. The patients were assessed clinically and radiographically.

RESULTS

The average duration of follow-up was twenty months. Eight fractures healed uneventfully at an average of 5.4 months. Three treatment constructs failed with fracture of the plate within twelve months after surgery. An additional three constructs also failed because of plate pullout. All failures except one occurred in constructs in which a cortical strut allograft had not been utilized.

CONCLUSIONS

On the basis of the high failure rate in this series of patients, locking compression plates do not appear to offer advantages over other types of plates in the treatment of type-B1 periprosthetic femoral fractures. Despite the potential to preserve the cement mantle, the locked screws did not appear to offer good pullout resistance in this fracture type. We believe that supplementation with strut allografts should be used routinely if this type of locking compression plate is selected to treat these fractures.

Separation of the apex hole eliminator screw in four failed hybrid total hip arthroplasties

Advancement or separation of the apex hole eliminator screw in uncemented Duraloc 100 cups (DePuy, Warsaw, Indiana, USA) has been recently reported as a radiographic finding without clinical effects. We report 4 patients with a separation of the apex hole eliminator screw in Duraloc 300 uncemented cups and aseptic failures of a hybrid total hip arthroplasty (acetabular osteolysis and femoral stem loosening). Revision surgery was performed when disabling pain and radiographic signs of loose components were present. Although difficult to determine, a relationship between the screw migration and the failure could have existed in these cases. Migration of the screw might not only be interpreted as a radiographic, clinically irrelevant finding. Its presence should alert the orthopaedic surgeon that the prosthesis is exposed to high intraarticular fluid pressures.

Histology of vancomycin-supplemented impacted bone allografts in revision total hip arthroplasty

Vancomycin-supplemented allografts provide biological restoration of bone stock and sound fixation with a low incidence of re-infection. Experimental incorporation of these grafts is similar to allografts without vancomycin. However, the underlying biology remains unknown.

We report the first histological observations of vancomycin-supplemented impacted bone allografts in two reconstructions performed 14 and 20 months after revision surgery because of a periprosthetic fracture.

Areas of active bone remodelling (creeping substitution), as well as calcified bone trabeculae and graft particles embedded in dense fibrous tissue, were observed with osteoid and fibroconnective tissue surrounding polymethylmethacrylate particles.

These pathological findings are similar to those reported in allografts without vancomycin and support the hypothesis that high levels of vancomycin do not affect the incorporation of bone graft.

High active local levels of vancomycin without nephrotoxicity released from impacted bone allografts in 20 revision hip arthroplasties

BACKGROUND

Cancellous bone can act as a delivery vehicle for vancomycin without impairment of graft incorporation. However, local and systemic antibiotic levels, biological activity of vancomycin, interaction with antibiotic-loaded cement, and also nephrotoxicity of these composites have not yet been studied clinically.

MATERIAL AND METHODS

Blood, drainage and urine samples of 20 consecutive patients undergoing revision total hip arthroplasties with impaction grafting technique utilizing 1 g of vancomycin per femoral head were studied. Plain PMMA cement was used in 10 cases, while PMMA with gentamycin was used in 5 cases and tobramycin was used in the remaining 5 cases. Biological activity of vancomycin was studied using kinetic killing curves in three ATCC organisms (methicillin-sensitive Staphylococcus aureus, methicillin-resistant Staphylococcus aureus and Pseudomonas aeruginosas). Quantification was done with fluorescent polarized immunoassay. Renal function was evaluated with preoperative and postoperative urea and creatinine.

RESULTS

Local active bactericidal levels of vancomycin reached 1400 microg/mL (average 5-point level = 367 microg/mL) without nephrotoxicity. Vancomycin was present in urine until the fifteenth day. Both aminoglycosides in the cement had activity against Pseudomonas aeruginosas.

INTERPRETATION

Local levels of vancomycin were 35 times greater than the highest levels reported with vancomycin-loaded PMMA. A synergistic effect was observed between vancomycin released from impacted allografts and aminoglycoside-loaded PMMA.

Vancomycin-supplemented impacted bone allografts in infected hip arthroplasty. Two-stage revision results

Bone allografts can store and release high levels of vancomycin. We present our results of a two-stage treatment for infected hip arthroplasty with acetabular and femoral impaction grafting using vancomycin-loaded allografts. We treated 29 patients (30 hips) by removal of the implants, meticulous debridement, parenteral antibiotic therapy and second-stage reconstruction using vancomycin-supplemented impacted bone allografts and a standard, cemented Charnley femoral component. The mean follow-up was 32.4 months (24 to 60). Infection control was obtained in 29 cases (re-infection rate of 3.3%; 95% confidence interval 0.08 to 17) without evidence of progressive radiolucent lines, demarcation or graft resorption. One patient had a further infection ten months after revision caused by a different pathogen. Associated post-operative complications were one traumatic periprosthetic fracture at 14 months, a single dislocation in two hips and four displacements of the greater trochanter. Vancomycin-supplemented allografts restored bone stock and provided sound fixation with a low incidence of further infection.